Procedure:(((((( Split this up into more paragraphs with pictures: ))))))

Prepare the car first.All E30's except early early cars ('84s) have ski-pass holes behind the rear seats, that the subwoofer will fire through. It is possible to cut the shape of the subwoofer and port holes into a seat back of a very early car by following the instructions for installing an E2110 / E2812. E30's also have a very thick tar under the trunk carpet, and it must be removed for the installation of our subwoofer enclosures. There are many ways to remove this tar, such as freezing it and cracking it off, or basically melting it enough to peel up. We have successfully used a couple of halogen work lamps with their safety cages face down on the tar to heat it up, then close the trunk. Check and move the lights every few minutes, and peel up the tar with a putty knife as it loosens up. You'll need to pull the rear seat out, and depending how extensive you're going, the driver side rocker trim, driver side knee bolster and other pieces to run RCA's, but this is not a walk through for that work. The seat bottom pulls up in the front with two clips near the front corners, and seat back is removed by lifting up and out after a couple 10 mm screws are removed. Now, you get to hit your car with a mallet! The ski-pass hole is perforated metal and will give way relatively easily with a heavy mallet. The subwoofer will be sealed against this hole.

Prepare the subwoofer enclosure.Begin by drilling a hole in the top of the enclosure above the subwoofer - this is for your audio cable to pass through. Use a drill bit for a hole that the wire will just squeeze into. Leave a generous amount of wire coming out of the top to be sure it will make it to your amplifier connections gracefully. The wire should be long enough inside the enclosure to easily connect to the subwoofer terminals. Wire up the subwoofer and pull the wire into the enclosure a little, so you can see the wire where it was passing through. Add a zip tie around the wire and snip most of it off, then run a bead of silicone sealant on the top of that zip tie around the wire. Pull the wire back through, and as the zip tie reaches the top it will seal the hole. At this point, bend the subwoofer wire towards the back of the box and secure it with a screw-eye zip tie and a short drywall screw. The box is ready to go in your car, minus your amplifier and associated amp wiring.

Install the subwoofer enclosure.It is time to put the subwoofer into the trunk, lay the carpet back down over the cleaned up trunk floor and move previously routed wires and such away from the box to the sides of the trunk. Push the box in, all the way forward until it stops at the seat wall. It may take some persuasion to sink all the way in, they are a very tight fit. On the border of the ski-pass hole in the top and bottom sides, you will use 4 coarse thread drywall screws to seal the face of the enclosure into the ski-pass hole. The drywall screws will sink through the metal, but small (1/8" or less) holes can be drilled as pilot holes. Do not use drill-tip screws. Once the enclosure is secured, the seat can be reassembled and wiring buttoned up in the trunk. The installation of the box itself is complete.